Costa has failed to find the net in his last 17 top-flight appearances, but he scored against Monaco in the Champions League in September and hit a double in Atletico's UEFA Super Cup defeat of rivals Real Madrid.
Defenders Diego Godin and Filipe Luis instead struck to send Atletico top, and Simeone feels goals are on the way for Costa, who had a powerful shot saved by his former team-mate Miguel Angel Moya with his side already two up.
"Of course, he is working so that the goals return," Simeone said at a post-match news conference after his side bounced back from a crushing 4-0 Champions League loss away to Borussia Dortmund, the heaviest defeat of his seven-year reign.
"He is extraordinary and very important for us, for all the things he does in the dressing room. If you play like he did [against Sociedad], you are very close to scoring. It is the way."
France international Lucas Hernandez was withdrawn at half-time as a precaution due to muscle fatigue, with Filipe Luis replacing the World Cup winner.
"At first [Lucas] started to feel a little pain, we knew that if he started feeling more, we would stop before there was anything worse," Simeone said.
"He has an extraordinary present and future and has Godin and Filipe that will not let him rest.
"They do not stop fighting. It is the strength of the team in recent years."
Simeone is now looking forward to watching Sunday's Clasico, although Atletico will be overtaken in the table by Barcelona if they avoid defeat against Madrid at Camp Nou.
"I care about today," he added. "[El Clasico] is a great game with two extraordinary teams, hopefully an encounter that we can all enjoy."